Does this mean that the person (who hasn't been playing for months) can pick up another, regularly played instrument and it sounds 'at its best'? Is it the viol

Does this mean that the person (who hasn't been playing for months) can pick up another, regularly played instrument and it sounds 'at its best'? Is it the violin which falls asleep or the operator (who hasn't played it much)? Because certainly the musician's skills (focus, nuance, whatever all lumps in - even sensitivity to musical content and musicality) slowly degrade without continual practice. I've noted over and over that my keyboard instruments get 'stiff' when unused. But so do my fingers, reflexes and skills. Which leads me to ask: isn't it both?